I'm getting sick and tired of seeing people say "oh, a 160 thermostat is too cold for our cars"! That's a load of horse s h i t!! I have a 160 thermostat and an adjustable fan swtich in my car and have had in my car for over 2 years now!! My car runs a cool 165-170 all the time!! The only reason you would even want your car above 170 is because the air/emissions stuff kicks in at about 170 degrees!! But if you don't have or have eliminated the air/emissions stuff like I have then you don't have to worry about running the car TOO cool....there's NO SUCH THING!! Especially on TPI, the cooler the air is in the plenum, the better the performance!! If the car is getting up to 200+ degrees like I see a lot of people running then the plenum is obviously not gonna be AS COOL and neither will be the air in the plenum, thus hurting your performance!!

 

if you want a cool intake charge, do it properly, set up a cold air induction!

*the warmer the combustion is, the more power you make.*

Goto the track, hang around some people that actually know what they are doing, sometimes in order to get the best time possible, guy will do "hot laps" that is make a run than immediatly line back up and run again while the engine is good and hot, they do this because they know that a hot combustion will get them more power.

so for the average driver, a cooler thermostat might *feel* stronger, but it really isn't, it's just that like you said, the intake is cooler. and the car will feel a bit more "torquey" but if the car is setup properly(CAI), a warm engine is ideal for better performance.

getting a cooler thermostat is almost as stupid as doing the "TB bypass" mod to cool the intake charge, neither are very effective "mods"

JMO.


------------------
WHO NEEDS VTECH, I HAVE VORTEC!!

1982 Camaro w/ mild L31
14.02@104mph
one legged..

 

oops double post

[This message has been edited by Jer82Z28 (edited April 07, 2001).]

 

Ive heard this before.
My take is that the colder the engine runs the more sluggish it is. I tryed a 160 and my temp guage dident even move. the heater dident work either. But slap in a 180 and thats where it runs. The cold mixture is air/fuel the cooler that is the more power you get. SBC's seem to love 200-215. If a lower temp made so much more power the car would run great after sitting over night and turrning the key and going. Does it? No! it runs like crap until it has had a few minuts to warm up. If a 160 works great for you than go with it. I just dont want anybody reading this and wasting 60$ on a hypertech low temp thermostat then crying about no power increase. Been there done that and learned better!ssc

 

I know we're talking FI, but my carbed L69 didn't do too well with the 160, and it kept throwing codes at me; didn't feel like paying Hypertech $$$.$$ for one of those chips just to compensate this and maybe get another horse or two.
Best performance, for my app, seems to come with the 180 I put in plus Jet fan switch, plus I bought a hi-flow pump, and bypassed the rad. tranny cooler with a small RV cooler (not suggesting if you're in a colder climate) This seems to keep my engine cooling at a better constant and lets my ECM operate correctly.
And to think this car ran all it's life with a 195 stat and a 238 fan switch!!

------------------
DR Stevens
1984 Trans Am 305HO L69
sucks gas, hauls ***
1991 Firebird 305 LO3
for days when I need a/c

 

I wouldn't run less than 180. To cool coolant can reduce combustion chamber temps to the point that fuel at the outside doesn't burn completely, which increases the amount of HC in your exhaust which is bad for emmisions.

------------------
82 z28 350cid, vortec heads, comp 262h cam, Holley 600cfm carb, 2in twice pipes, MSD ignition, turbo 350 trans, 3.73 posi, manly b&m megashifter

 

Let's start at the top!!

So you're sayin' the guys that ICE DOWN their intakes between runs are stupid?? Sounds like that's what you're tryin' to say to me!! Look again!!

First off, when my car runs between 200-215 it runs like complete s h i t!! And YES, my car runs AWESOME first thing in the mornin' after setting over night!! Runs like a raped ape and after it warms up a bit, the performance starts to go downhill!!! Second, no one said anything about a HyperCRAP thermostat!! I wouldn't buy one of those if my life depended on it! I'm using a $2 STANT 160 thermostat from the local parts store!! And about "no power increase".... I don't run a 160 for better performance! I run a 160 for piece of mind...... it's common knowledge that more heat causes quicker wear and tear on an engine!!

What emissions...LOL!! Like I said in the original post, if you don't have or have gotten rid of your air/emissions crap then there's no such thing as running TOO cool!! If you still have emissions, or NEED to keep emission because of your state laws....well, I feel sorry for ya!!

 

there is no piece of mind to it. optimum engine temp on a dyno for a tpi engine is around 168 to 177. the whole point is to lower air intake temperatures as well as oil temps. but running too cool will also lower combustion temperatures which defies the whole point of going for more power. i run 160 in everything, but timing has to be compensated for it. stock timing along with lower temps will just cause more harm than good. i personally never run anything but a 160 and never have a problem with heating, but i also make compensations with tuning to make up for it. running the lower temp. theremostat though does cause a problem for those with cooling fans that run all the time and take alot of short trips. it causes moisture to build up in the engine. with electric fans i never set them up to come on until about 195. usually they'll never even come on in traffic in a good running car with adiquate cooling. i agree that the 160 don't hurt anything and even living in michigan i never have a problem with heat, but it's not just a put in part and go item. (by the way, where did you get a stant t stat for 2 bucks)

 

I have a 160 in my car and have passed California smog no problem. But was thinking of putting in a 170 as I noticed my temp gauge on my car does not get above 140 or 150. It is just the stock gauge on car and not sure how accurate it is. Is their a way to get a true reading on water temp besides a mechanical gauge? I do not drive car often and when I do mostly freeway. I really am getting somewhat confused on this tempeture issue. I am sure you have to take a lot of factors into consideration. Or what was said in a earlier post about making a few adjustments.

 

86TpiTransAm: your not very bright are you?


when did I ever mention that?
Iceing down the intake is a great thing to do at the track, however do you see them icing down the block to cool the whole engine? NO!

"hot lapping" will only work if you can keep your intake cool, but like a genius you can't seem to grasp that concept.

What I'm telling you to do is get yourself a cold air induction system and you will realize that a cold thermostat is not needed.

like I said before, swapping thermostats is the half@ssed way of reducing intake temp, and causes emissions problems and makes your engine burn less efficiently.

sounds like a ***** mod more than anything.

oh and if your engine runs so great in the morning, why don't you plop a 100 deg thermostat in? then you would have TONS of power!!!

------------------
WHO NEEDS VTECH, I HAVE VORTEC!!

1982 Camaro w/ mild L31
14.02@104mph
one legged..

 

If we are just looking for information then:

I run a 160 thermostat and both fans on all the time. Even in the winter, my temps get up to 160 pretty quickly (5-10 min). On warmer days and if I drive for a while (30+ min), then the temps will go up to 180 no problem. I pass the sniffer this way too.

I am fighting a cooling problem though. Next weekend, I am putting in a Griffen radiator and will most likely install a 185F thermostat. I will also put one of the fans on a switch if I can ever get that plug out of the intake!

------------------
1984 z28 w/ a 357 cu in. monster engine which is looking like the posterchild for Edelbrock with the exception of the Holley 750vac... all the suspension stuff... 9-bolt posi disk is in...

-=ICON Motorsports=-

 

Yes, your engine will run with a 160 t-stat, and yes, your emissions will suffer. Keep in mind that regardless of AIR and EGR being inoperative, the ECM doesn't modify the BLM until 173*F. The ECM is relying on a default table for spark and fuel delivery, so depending on your level of mods, you're actually working against yourself. I'd like to open the floor to Glenn or Trax, they can pick apart ECM's in their sleep better than I can awake.

------------------
-Jason M. 1991 Camaro Z28

 

Let me tell you about my experience w/ all of this.

First: Cold Air Induction is a MUST. I went from a throttle body mounted air filter, to a CAI setup that I built myself, and shaved a consistant, time slips to prove it, two tenths.

Second: I also ran my car at the track, and after several "hot laps" I recorded my best time. Than I let it sit for three hours, hood up, then ran again. Shaved two more tenths. Also shaved .1 off the 60 ft. Did I launch better or hook up better? Maybe, I don't know, but I have always noticed the car runs stronger when its colder. I have run all of my "best" times w/ the car sitting for awhile. Then once it gets hot, I usually lose about .2

Not supporting anybodies theory, just submitting my $.02

------------------
If you live in Southeastern US, check us out!
South East Thirdgen

GM Master Tech
ASE Master Tech + L1
Savannah, GA

'87 Trans Am
S/D TPI retrofit including functional PassKey,
22# injectors,
Whatever chip I feel like burning,
JET AFPR, Ported Plenum,
TB Coolant Bypass, Custom Cold Air,
SSM SFC, KYB Shocks, Boxed LCAs, Wonder Bar,
8mm Accel wires,
Flowmaster Exhaust,
16" GTA rims,
Corvette Servo,
-->14.97 @ 94.9 MPH<--

'97 Bonneville SSE

 

for the guy running your fans all the time. kinda defying most of the point of running the colder t stat. that's one hell of a draw on hp running both of them fans. the alternator still has to put out the charge for them to run and draws away power to run them. most cars can run without fans at all on the highway and rarely need them in the city except real low speeds or heavy traffic. not only are you taking away power by running the fans all the time, but your putting alot more stress on your alternator.

 

A colder T-stat will make your engine run richer unless compensated for in the eprom.

If you need more fuel, then this MAY be beneficial. But for a "basically stock" engine, the stock GM memcal is set too rich as it is and this will just compound the problem.

If you DO wish to run a cooler t-stat it should be fully compensated in the eprom though. There are a LOT of factors effected by a cooler t-stat that can result in "inconsistent" performance.

I too ran a 160* T-stat for many years and I did find that it did cause me to burn more fuel and caused my engine to run too rich. Also, your idle is affected as the engine will slowly decrease your idle speed as the engine gets warmer. The stock GM memcal will cause your engine to idle faster with a 160* T-stat than a warmer T-stat.

As for the time to reach 160*F, that is irrelevant between the different T-stats. Both t-stats will remain closed below 160*F and heat the engine at the same rate of speed (if everything is normal with your cooling system). Also, as for being too cold for the heater, it really depends on your tolerance to cold weather. While my 160*F never made my interior feel HOT (during the winter) it wasn't freezing cold either.

As for the effects on the incoming air charge between different T-stats, I found the effect to be minimal. I bypassed my coolant to the TB and with both a 160* and 180* t-stat and taking a scan tool reading of the MAT on the same day and driving down the same road, I found minimal difference between the MAT readings. I compared these driving down a open highway to make sure "heat soak" to the plenum did not effect the "in plenum MAT" reading.

 

No doubt... so that is why I am putting one on a swich next weekend. However, my radiator is shot and I need both fans or else I'll overheat and that is really bad for performance...

------------------
1984 z28 w/ a 357 cu in. monster engine which is looking like the posterchild for Edelbrock with the exception of the Holley 750vac... all the suspension stuff... 9-bolt posi disk is in...

-=ICON Motorsports=-

 

First of all, I HAVE CAI!! Guess you shoulda asked before opening you're mouth about that one!! Also, you keep talkin' EMISSIONS!! I don't have emissions....I don't know how many times I've said that!! Wow...you sure are a smart one!

Again, no emissions!! BUT, around town my car runs right about 173 degrees..sometimes cooler... and out on the highway it gets up around 185-190 in the summer mainly because I have a TH350 that runs high RPM's on the highway so I really doubt my efficiency is hurting!! Once I put the 700R4 back in I may find it different, but I doubt it since the summers get VERY hot here in MO!! My friend has a carbed car so it's a bit different... but even he runs a 160 t-stat in the summer!! Although he switches to the 180 in the winter because his heater doesn't get hot enough!

As far as my engine idling faster with the 160...it doesn't!! I've reset my timing, adjusted my fan switch, and reset my idle appropriately and it idles smoothly between 650 and 700 RPMs in drive! My ECM is still STOCK!! It took me awhile to get everything in sync with each other but it is now and I can honestly say I don't think my STOCK 305 has ever run better!!

Ya know, maybe I'm just paranoid about my car running hot since the engine in my '80 Firebird got screwed from running too hot!! All I'm sayin' is that I know what my car likes....it's the 160 t-stat, and I just don't agree with people who say the 160 is TOO COLD for our cars!! I honestly think it all depends on WHERE you live and what WORKS for your car!!

 

Someone needs to close this. No point in argueing over something so stupid, and no i'm not takeing anyone's side. As far as what's better? It's not my choice, it's not vaders, its not gmtech's, its the drivers, test it at a track, if it works for you, okay neato...then lets leave it alone.

------------------
89 IROC-Z 350 TPI

-Flowmaster Catback
-Performance Resource Chip
-700R4 (Rebuilt) Too much done to actually list
-K&N Airfilters
-Ported Plenum
-2.77 Gears (not much to brag about but eh, its there)
-MSD 8.5 mm plug wires
-Gutted cat
-!AIR

 

why dont you remove your stat and have your fans running constantly? this would make it even cooler = better performance

 

Like Glenn said it's all relative to the settings in the Eprom. If you set it up to function with the 160 everything works great,
if not, you will have problem areas to deal with. On my own race car, I always tried to pull to the line with the temp. in the 130-140 range. Yes, that's because the engine does make more power when the air and fuel charge is cooler (hence the ice). Just my $.02

------------------
Chronologically challenged. But still kicking!
'92 CAMARO RS
305 TBI 5/spd (now TPI)
B4C Alt.
'69 camaro-BB/Lenco,1050 dominators, /Pump Gas/no drugs 8.97-150+/3200lbs.
SoCal Thirdgen F-Bodies

 

Over a year ago my 190 ts broke & I replaced it with a 180 as thats what was available. My car always seems to run around 155 degrees except in traffic. The other week I tried a 160 as that seemed to be a commen mod & noticed very little difference maybe 5 degrees. After reading all the controversy, I struck middle ground & put in a 170. Again no real change.Is my car running cooler than everyone elses because its a manuel, no a/c or emissions or I just drive faster (more airflow)?

------------------
84 Trans Am HO L69 WS6
5 Speed manual
Vortech Cherrybomb no cat
Removed A/C A.I.R. Hdflap
H/made cld air induction
K&N
Otherwise STD

 

How are you determining the temperature you are running at? Scan tool is the only accurate way (provided the CTS is operating properly...which is necessary for the ecm).

The temperature guage is highly inaccurate and should not be relied upon EXCEPT as a general indicator.. but not for accuracy.

 

Like glenn said, the mechanical gauge is NOT a good indication of actual coolant temperature. I too believed it was at one time.

I just got the Diacom Diagnostic Software, and let me tell you.......

The coolant temp. gauge reads about 172º +/- 4º constantly when I'm warmed up. When I hooked the Diacom up, I read between 188º-190º at full warmup.

Now, I'm one of thoise guys that's very tideous when it comes to reading gauges, and according to my gauge, each incriment is 12º. Well, our gauges (and any mechanical gauge for that matter) is in no way linear....so never rely on a mechanical gauge to read an accurate temperature just as Glenn said....Okay, I'm off base here, I'm done....

------------------
86 Trans Am WS6 Black with tinted windows, shaved door handles
ZZ4, Mini-ram, true duals
***Too many other mods to mention***

"In the future, cities will become deserts,
roads will become battlefields, and the hope of mankind
will appear as a stranger" The Road Warrior

[This message has been edited by Steves ZZ5 (edited April 08, 2001).]

 

Well, there were some flames outta nowhere..

Anyway, I ran a 160 in the RS for a long time, went to a 180 this winter, car ran much better, and alot faster.

I'm sticking to 180 on my TBI car.

If I had a TPI car, I'd try a 160 first, and go from there.

No need to get so defensive dude..

 

Well I guess I'll pitch in here...I have a stock prom in my 89 tpi iroc and the stock fan switches. The car seems to run best when slightly warmed up but not TOO warm. I'm running a stock thermo after trying 180 and 170. The problem with 170 or 160 is that in stop and go driving your temp will get HIGHER than it would with a 195 in there because coolant is not allowed into the block before it gets down to 160/170. So imo, the colder stat will make for much larger FLUCTUATIONS in temperature (at least with the stock prom and fan switches) which to me seems worse for engine life than a more constant if higher temp. (head gaskets come to mind)

On a performance note, one mr. smokey yunick has found that small blocks run best in the 210-220 range for combustion chamber temperature. I'm not sure what that translates to for coolant temp. Does anyone have any info regarding this? I.e. what is a typical "stock" tpi thirdgen combustion chamber temp with a stock thermo and how far from optimal is it?? Then we'd need to find out what the precise relationship between coolant temp and chamber temp is, and finally we could then configure cooling systems optimally. For now I'm going the way of GM Tech with a stock thermo and cold air.

 

Ok...the purpose of the original post was NOT to say "hey, you should use a 160 because it's better"!! The purpose was to tell people to QUIT saying that the 160 is TOO cold because it's misleading! Yes, it may be too cold in SOME of our cars! But not in ALL of our cars!!

Just for ***** and giggles I may put a 180 or 195 in this week just to see what happens because it has been 2 years since I switched to the 160!! Don't think it's gonna make that big a difference in a 200,000+ mile engine like mine tho'!! I'm predicting the hotter t-stat is going to make my engine ping and knock....but then again, maybe I'll just need to retard the timing a bit! We'll see!

 

86TpiTransAm, you have to understand what Jer82Z28 is telling you. He is talking about a hotter BLOCK. Yes having cooler air coming IN to the engine is always better..however more power is made at a higher temperature. You are confusing coolant temperature with combustion chamber temperature.

When I was 100% stock, I switched to a 160degree stat and noticed a HUGE decrease in performance. The car felt sluggish. I put the 195 back in and it runs great. I now run a 170* (really runs at 176degrees). The blower makes the incoming air rise to around 170 degrees anyway.

cold t-stats suck and make you get bad mpg. GM engineers knew what they were doing.

------------------
91 Formula 1LE 1 of 46
305 TPI 5speed
1LE/G92/WS6

Paxton SN92 supercharger, Ford SVO 24#injectors, Crane AFPR,SLP airfoil, ported/polished plenum, March alt. pulley,Crane Gold 1.6rrs,MSD coil,MSD6AL (5400rpm limit),Holley 9mm wires,Ac delco R43ts plugs,custom chip,Bosch O2sensor,SLP 1 5/8" headers,SLP catback,shortened shifter,3:73s w/Auburn posi,180* t-stat,JET 195* fan switch, Macewen white face gauges, Autometer gauges, Zoom hi-performance clutch.

 

I wonder why most NASCAR series try to run their water temps at about 210 degrees by adding/removing tape from the front end of the cars (per Larry Mac)? You would think if you build more HP at lower temps they would do all they could to lower temps not raise them.

 

Obviously this guy has a real "race car" . I dont think explaining thermodynamics and four cycle engines would do any good here, but 160 is less than optimum for piston expansion and ring seal in the cylinder. Your best performance comes from a oil temp around 200 deg and a cool dense intake charge. For street cars a 180 stat is about perfect, regardless of emissions. Im sure your car is faster when it sits and cools a while, most 15 second cars do run better. If you were to keep your internals around 200 and your intake cool you might break the 14 second zone!!!!!!!!

------------------
87z 383,afr 190's, comp hyd roller(242/248-.540/.562,114 sep),Ported and polished mini ram, 30lb inj, 3.42 gears, tremec 5spd, , 1,3/4" slp headers, speed pro bank to bank-wb02.
"Just remember children, no man can beat you once youv'e found the cliterous." 'chef'

 

Nascar uses race gas, so detonation isn't a concern. The reason for a 160 thermostat is to lower combustion chamber temperature to prevent detonation. The PROM's that are made for these low temp's have extremely agressive fuel and spark curves which would result in detonation at higher temperatures.

 

You guys should keep in mind that running a colder tstat in a dry flow manifold (TPI, MPFI, SFI) is a completely different subject than running one in a wet flow manifold (carb, TBI).

I have no experience with dry flow (yet), but my experience with wet flow is that YES, 160 IS too cold. You WILL have problems with fuel puddling, which will cause a lack of power, bad gas mileage, worse driveability, etc. especially in the winter months, when the 160 thermo is ACTUALLY keeping the coolant at around 160 (not during the summer when the cooling system can't keep it below 180 no matter what thermostat you run)

I would never again run anything colder than 180 on a wet flow fuel system. It's just a lose all the way around.

------------------
"Beware he who would deny you access to information, for in his heart, he dreams himself your master"

'84 Black Camaro ZZ4 M5 (V-6 in a former life) -- street beast
'91 Medium Blue Metallic Z28 A4 (UB-HSTRY's old ride) -- currently broken
'99 Navy Blue Metallic Firehawk #120 M6 (99.44% stock) -- daily driver

 

Ive found that a cooler stat increases the chance of detonation. The air is denser, the atomization is decreased... I can see it in my EGT.

87Zya is exactly right on the other counts. Cold engine temps make for a loose motor that leaks more cyl pressure in the form of blowby. This is compounded by the fact that GM programming at 160 deg. is still in warm up mode. I too ran a 160 stat for the longest time before I knew anybetter. Much more consistent performance with the 180, less gas consumption.

 

OK, good point, a 160 stat isn't technically too cold, the car will still run, and may in fact run a little better. From a general advice standpoint though, it's bad practice. Your engine will live the longest, and run much more efficiently at higher temps. Maybe you'll run a little faster, maybe you won't, but it does have disadvantages.
...ed


------------------
Ed Maher - Moderator @ The Carb Board
92 Z28 Convertible - Quasar blue / Tan top
LB9 4L60 GU2 G80 - stock, soon to be sleeper
-=ICON Motorsports=-

- Definitely prototypes, high powered mutants of some kind. Too weird to live, too cool to die

 

Maybe I shouldn't jump in on this one
Here goes

You have to balance everything! Too much fuel not enough air=probs. Too high temp, low grade fuel=probs. MSD ignition, wrong wires=problem. The list can go on. If stock, leave thermostat alone. Hell, all it does is open and close off coolant, a 180 degree is full open at 180, it is still open at less temps, and is never completly closed.

So just balance out your mods!


------------------
Corry Lazarowitz
clazarow@voicenet.com
clazarowitz@hotmail.com
SLP 1 3/4" headers, 3" cat back (stock cat )MSD ignition. MSD Blaster SS coil. More soon when funds are avail...

 

One thing that I wanted to bring up here that nobody has mentioned (unless I skipped over it) is that the SBC cooling system is crappy. The rear cylinders always run much cooler than the front cylinders. With a 160 stat this causes the rear cylinders to run REALLY cool. I used a 160 stat for a couple years and I was a huge supporter of running one. However, I went to a 180 after I tore my engine down for a head/cam swap and witnessed the cooler running rear cylinders.

A 180 stat seems like a good compromise to me. That is what I am going with (along with the PROM changes to make it work correctly).

Tim

------------------
TRAXION's 1990 IROC-Z
Best Time = 12.244 @ 112.51mph (1.778 60' / 7.819@88.32mph in the 1/8)
All Natural. No Force. No Drugs. Stock Bottom End. Stock Body Panels.
Gunning for NA 11's with bigger cam, bigger stall, and bigger exhaust.
-=ICON Motorsports=-
Moderator: PROM board at thirdgen.org

 

However, if you live in pheonix like I do a 160 thermo is about all you can do to keep your car from boiling over.

------------------
91' red RS convert.
71,000 miles
89' IROC hood
red Z-28 16" rims
potenza re730's
MSD ignition
MSD coil
K&N fiter
350 ported polished heads
hypertech chip
flowmaster 40 series cat-back

 

This seems to be a big issue. I have to agree with Pablo about the wet flow. My TBI system seems to run better with a warmer stat. 180 is great, not too cold and not too warm. 160 is like he said, still in warm up stage. I liked the performance from my 305 TBI with the 160 thermo when the only mods I had was the hypertech thermomaster chip and SLP headers & exhaust. The old thermo was a 195 and the car ran okay and I even tried the ram air through high beam thing for cold air, ripped off that thermac crap and did all the ultimate TBI mods. Maybe it was the crappy design of the L03 swirl port heads, I don't know but my car did like the 160. Maybe it was because of the chip itself, who knows. I think from what I've learned and heard from guys at the track (Englishtown and National trails) I'm going to use a 180 from now on. 180 seems to be where it's at, it's just above the GM warmup and it's still cooler than the 195. I don't like people saying GM knows what they were doing. That just says we should leave it all stock. Yes they knew what they were doing but it wasn't just for performance, it was also emissions and other reasons for the higher stat.

------------------
, Jon (350 TBI! getting 23mpg highway)
91 Red RS w/grey int, sq stereo (Alpine v12, kicker solo, MB quart premium etc)AIM: JPrevost

• Holley 670 TB unit w/ 1/2" spacer/adapter
• Edelbrock RPM vortec intake
• 350ho 330hp vortec crate motor
• 8" harm. balancer
• Stewart stage 2 water pump w/160 thermo
• SLP tri-y headers to full 3"
• Rebuilt trans w/ SLP shift kit
• Centerline 16x8's all around
• 36/24 mm sway bars
• Full poly bushings, even motor mounts
• SLP LCA and panhard
• Alston SFCs
• Edelbrock 3 point STB
• Global west steering brace aka wonderbar
• Eibach pro kit springs
• Bilstien high perf. struts and shocks
• All this and I still have AC

My websiteAny questions?

 

This is what I think about it. hehe


------------------
'87 Trans Am:
(Engine)
305 TPI
160 Degree Thermostat
TB Bypass
Accel 300+ 8.8 Racing Wires
Accel Super Coil
Bosch Platinium Plugs
Custom Ram Air with K&N
Removed Emissions Equipment & Cat.
(Stereo)
Kenwood Excelon

 

Last I checked a cooler stat decreases the chance of detonation. That's why we buy lower temperature stats when we get crappy Hypertech ships that only advance the timing... When I ran my 195* stock stat for those 2 days with the chip in, I had a whole lot of pinging that ceased as soon as I switched it for my 180.

------------------
1987 Camaro Sport Coupe LG4
700R4 with 2.73 open rear
Hypertech chip, 180* stat
L69 Dual snorkel air cleaner with K&N air filter
CK rods with B hanger
Hooker catback
Pioneer DEH-P4000, Pioneer speakers front/back

 

if your car is going to over heat it will do it with anythermostat as they will all be open beyond 195 degrees. The thermostat just sets the lowest operating temp of the engine coolant. So if its overheating look at increasing airflow across the radiator or checking or water to coolant mixture.


as for cooler engines detonating less.. On a well tuned engine.. tuned for each operating temp, I believe the engine will knock more at either extreme of the spectrum. I can comment on what I have witnessed on the cold end. That is, that it has a greater propensity toward detonation when the engine is cold via EGT. I believe Glenn has witnessed this aswell in testing if im not mistaken.

 

Wet flow systems are much different than dry flow. So temps need to be higher to maintain the fuel in suspension. A car with a chip made to run a 160 degree stat will detonate more at higher temp because the chip is using a very lean A/F ratio and greatly advanced timing. Both cause combustion chamber temperatures to go up, thus detonation. If you have a cold engine and the gas isn't staying in suspension you get a lean condition again conducive to detonation, that is why you can get it on a very cold engine and a very hot engine. Also running lower temps sometimes allows the fuel to come out of suspension when it contacts the cold cylinder wall, this washes down the cylinder wall removing the lubricating oil and causing rapid ring and cylinder wall wear. Carbs and TBI's are the most susceptible to this because their fuel isn't atomized as finely as it is in a PFI engine.

 

This is probably the most accurate question here. Ideally, you want a warm engine, hot oil (like 210ish) and cold air coming in the intake. IMO the TPI, even though the plenum is above the base and its aluminum, makes an excellent heat retainer and hurts performance. Thats why you see different cars and combos running differently. Different intakes, induction, air inlets, etc.

Running a 160 will hurt mileage, raise emissions, and on a TPI it can make more power if the rest is setup right. Some cars dont run rich out of the box, like my 86. It was always lean, and after I changed stuff I made it worse. It ran much better with the 160, simply because it was too lean to begin with and the intake was colder as well which always helps.

I dont see how you can relate a lower temp to detonation. Detonation is caused by hot spots in the cylinder, and if you have detonation at a colder temp, its from running lean not from the colder temperature. Coolant at a lower temp will run the block temp and chamber temp lower if everything is working right, so any hot spots at that point are an indication of some sort of tuning problem. The detonation king is sitting in the backyard here right now, and it was worst on 90-100 degree days, with an engine temp of about 190. Colder was definitely better. I have played with detonation in other cars, and it seems that warm air and hotter engines dont get along well at all in that respect.

Saw something too about overheating... all a lower temp stat will do is make it take a little longer for the car to overheat.

 

jeez, l cant beleive this argument. this is almost as lame as the dual exhaust vs. single exhaust. l mean come on, 160 vs. 190 doesnt make a difference. come on! its a small 305 or 350 whatever small block its not like its a super tuned super charged nitrous injected 502 its a small block fairly stock with emissions crap removed! someone said a thermostat change is like a ***** mod, its the same as changing your spark plugs and saying you got a 10 HP gain. its ridiculous, if someone like their 160 GOOD FOR THEM! if it runs good GREAT! lm just sayin its not gonna run any better and its not gonna run any faster. l've seen 170,000 miles on 305's stock. please dont tell me a thermostats gonna make your motor run better, its gonna throw out codes left and right. and its a 30 degree difference which equals about a 3 HP gain, well good work, that 3 horses probly got sucked up in the driveline. congrats you wasted 2 bucks

 

For everyone who says that a cooler temp thermostat is going to hurt gas mileage you're full of s h i t!! Come to Missouri (Southwest) and I'll show you!! I've run a stock 195 t-stat and my 160 t-stat and have seen ZERO change in gas mileage!! You can talk and talk about what books say and what YOU'VE experienced yourself but you NOT going to change my mind!! I've tried it all and I KNOW what works "efficiently" in my car!

 

www.stewartcomponents.com is a great site regarding cooling systems. I just read alot of myths here regarding this topic. One thing I want to make clear and this site will back it up is, running a cooler engine is beneficial powerwise, won't be good for fuel economy(emmissions).

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Big 454 72 Chevy Nova
383 86 Camaro Z28
10.5:1compression 186 casting Heads,234dur.488lift exh&int,Edelbrock performer intake, Holley750 vac.sec 400 crank,flat top pistons,edelbrock valve springs and lifters,tranny shift kit,kickdown kit and tranny oil cooler. Will install 3.73's later on and might go with a more aggresive cam.

 

86, so have I. 180* worked better. Trust me, I was a big advocate of the 160* T-stat until I got into eprom burning and discovered the truth with quantifiable results.

The bottom line is, with your TB bypassed and running on the open road, there is MINIMAL difference in the incoming air temperature as measured by the MAT...so it really doesn't have that great of an effect on the incoming air temp.

And there ARE a lot of little routines within the eprom that are dependent on the CTS which affect performance.

I was able to compensate for most, but I just found the 160* less consistent and it DID burn more fuel (we get cold here too).

I found tuning for the 180* gave more consistent performance, yielded better gas mileage and allowed my interior to get a little warmer on those cold freezing mornings. I just don't find any advantages to a 160* T-stat and the 180* does have a definite advantage...keeps the wife from *****ing from the "cool" interior when the weather is cold.

 

My experience is just the opposite.

Diacom reports temps 12 to 15 degrees lower than my digital dash reads. I'm running a 180 stat to.

The only thing I can figure is that the ECM takes it's temp reading from the sensor that's located in the front of the intake manifold near the thermostat housing, while the dash board gauge takes it's temp reading from the passenger side cylinder head.

Coolant in the head is hotter than in the intake manifold.

Jake



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1986 Corvette Coupe, 415 CID, Edelbrock 6073s, ZZ9

 

Jake, the CTS in the front of the motor is screwed into the block, not the manifold, and the temp gauge takes its reading from the temp gauge sending unit on the driver's side head, right next to the #1 spark plug (at least on my 305 tpi - I know because I have disconnected it and checked it). The CTS on the passenger side head is a fan switch for the secondary fan (also controlled by the A/C pressure switch).

Well, in my experience with the 160* stat, there was a marked power increase over the stock 195* unit, but the motor always seemed to run too cool. The heater worked marginally at best in the winter, and the motor just seemed to run a bit rough. Fuel economy was also way down. Switching to a 180* stat cured the heater problem, made the motor a lot smoother and just a lot more consistent (power was sometimes up and sometimes down with the 160). Best of all, there was no apparent loss in power or throttle response with the 180. Fuel economy was also restored. In fact, it's better than it used to be with the 195*. Probably because I don't have to dog the motor as much now.

BTW, I had a bad detonation problem with the 160 that is now gone. I wonder why.

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'88 IROC 305 TPI
Crappy 700R4 slushbox
Gutted airboxes
180 degree T-stat
Advanced base TPS voltage
Relocated IAT sensor
Momo steering wheel (gotta luv it)
Ram-air setup coming soon
Flowmaster muffler (puke)
Taylor SpiroPro wires
Accel cap and rotor
Ported plenum
Kills: '94 Z28, Olds Aurora V8, bunch of Mustangs, T-birds, ricers, and others who assumed a 12 year-old car would be too slow.

[This message has been edited by 88irocz28 (edited April 11, 2001).]

 

The CTS is in the intake manifold somewhere on every engine used in thirdgens that I can think of.

 

Hello all, this is my first post here on this site. I have learned a lot from just reading all the posts and tech articles. I switched to the 160 stat and noticed a decrease in performance. I lost 2mpg as per my computer and after reading the posts here will be switching back this weekend to a 180. I paid 3 bucks for my tstat at discount auto w/gasket.

BTW- Jakejr is right the CTS is located on the intake right by the tstat housing (I have an intake on my computer desk in front of me as I type this).

Jeff